Adsorption of acid red18 dye from aqueous solution using single-wall carbon nanotubes: kinetic and equilibrium

ABSTRACT

Dyes or colors are one of the most important chemicals used in textile industries. It is necessary that dye-contaminated wastewater before discharging to environment treated by an appropriate and effective method. In this study, the performance of single-wall carbon nanotubes (SWCNTs) as an adsorbent for the removal of dye from aqueous solution was evaluated. The effect of operational parameters, such as contact time, solution pH, adsorbent dosage, and initial dye concentration was studied. Adsorption data were analyzed using Langmuir, Freundlich, and Temkin adsorption isotherms. The Langmuir isotherm (R² = 0.9844) was the best fitted graph for experimental data with maximum adsorption capacity (q_m) of 166.667 mg/g. The kinetic data were tested using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The results of this study indicate that SWCNTs can be used as an effective adsorbent for the removal of azo dyes.

Keywords:

• Carbon nanotubes
• Adsorption
• Azo dye
• Kinetics
• Equilibrium
• Isotherm

Acknowledgement

Authors would like to express their gratitude to the Deputy of Research Affair Tehran University of Medical Sciences, for their financial support and assistance.